ABSTRACT The global burden of disease caused by microbial pathogens remains one of the largest challenges facing the international biomedical community. Among the leading causes of mortality worldwide are the causative agents of AIDS, Malaria and Tuberculosis. Furthermore, many of these microbes are resistant to multiple antimicrobial therapies, highlighting the need for new therapies and vaccines. The increased knowledge of the complex interactions between the pathogen, indigenous microbiota and host immune system that our Training Program offers to pre-and postdoctoral fellows will lead to new ways to treat, cure and prevent various diseases. The Department of Microbiology and Immunology at Stanford University runs a world class training program in Host-Pathogen Interactions and the program stands on four pillars: talented students/postdocs, committed faculty, rigorous and thorough training, and a dedicated university staff and infrastructure. The program is multidisciplinary and has tremendous breadth and depth. We study many aspects of host-parasite interactions? the microbe (viral, bacterial or protozoal), the host and together as a system. Our interests range from the discovery of new antimicrobials, the development of better vaccines, the discovery of pathogenesis pathways and the understanding of mutualistic interactions between host and microbe. Furthermore, we develop techniques for monitoring these interactions, like mass cytometry (CyTOF), bioluminescence imaging and culturing and screening techniques. Whole animal models from flies to mice are used and our state of the art Human Immune Monitoring Center now allows us to expand our work in human biology. Our students and postdocs are successful, publishing high-impact papers and finding terrific positions in all aspects of science, from research to teaching to policy and consulting. We have been recruiting an average of 6 pre-doctoral students in M&I and approximately 14 postdocs to the departments of participating faculty members per year. We use the training grant to support the first three years of our graduate students' education and one (or in exceptional cases, two years) of funding for select postdocs. We are requesting to increase our present level of funding for pre-doctoral slots to 8 and maintain funding for 2 postdoctoral trainee slots. The grant has been active for the past 30 years and we are requesting another 5 years of funding.